Printed circuit board connector



March 16, 1965 D. H. JAMES 3,173,732

FRINTED CIRCUIT BOARD CONNECTOR Filed Feb. 9. 1962 1 r 2? ?IN TOR.

DAVID H. JA ////////////////////X ,Z &W waw A TTORNE Y.

United States Parent Ofiice &173332 Patented Mar. 16, 1965 3,173,'732 PRINTED CIRCUIT BARD CONNECTGR David H. James, Huntsviile, Ada assignor to Tle Brown Engineering Company, Inc., Huntsville, Ala., a Corporation of Alabama Filed Feb. 9, 1962, Ser. Ne. 172,264 13 Clairns. (Ci. 339-437) This invention relates generally to connectors for interconnecting two or more printed circuit boards in a composite circuit where space and the need for interchangeability do not admit soldered connections. It relates particularly to an assembly of interchangeable spring contacts and connecter blocks of general applicability for interconnecting a pair or more of circuit boards in different configurations, supplied in each case With a row of terminal strips along the edge of the board, which circuit boards are to be interconnected to form a composite circuit, sometimes referred to as modular construction.

Since the development of printed cireuit techniques or circuitry mounted on a panel or board having printed or surface-imbedded interconnecting circuitry, it has been desirable to provide for interconnectors between such panels and from the circuitry of each panel to associated apparatus. Several types of terminal strip for this purpose have been devised, each of which has its known disadvantages, generally requiring considerably more space than is desirable. Devices of this sort have generally permitted interconnection of such rigid boards only in particular ways, such as to limit their usefulness. Such devices have merely permitted the insertion of such a board into a slot which then makes connections to some other apparatus or to auxiliary circuitry. In any such interconnecting devce, whether for rigid circuitry boards or for fiexible plastic cables having conducting circuits parallel-arranged along the length thereof and terminating in a -row of transfer terminals, a prine requisite of the interconnecting terminal strip is small size and lightness of weight to a degree heretofore not realized.

It is, accordingly, an object of this invention to provide a small connector terminal strip of light weight and general applicability.

Another object of the invention is to provide a terminal strip for the interconnection of two circuit boards or cables such as to secure the boards in a parallel array, either with one turned back upon the other, or With the two in substantial linear extension of each other.

A further object of the invention is to provide a connector in which two circuit boards may be interconnected at right angles.

Still a further object of the invention is to provide a connector in which three terminal boards may be arrayed, two in parallel and a third at right angles thereto.

A still further object of the invention is to provide an assembly of terminal strips for the interconnection of a considerable number of terminal boards spaced closely to each other for the compact assembly of a group of circuit boards.

Yet another object of the invention is to provide a universal block adaptable to receive a variety of contact spring elements for the interconnection of two or more circuit boards, each Contacting element of a connecter being selectable to interconnect Contacts on any two of three circuit boards on the same block.

Other objects and advantages of this invention will be more clearly understood as the description proceeds in connection With the drawings, in which:

FIG. 1 is a front elevation of a form of the Connector adapted to receive crrcut boards on upper and lower surfaces thereof;

, thereto.

FIG. 2 is a cross-section of the connecter of FIG. 1, taken along the line 2-2 of FIG. 1;

FIG. 3 shows two terminal boards attached to opposite sides respectively of the Connector of FIG. 1;

FIG. 4 shows a front elevation of the Connector of FIG. 1 having a different form of spring contact elements attached thereto;

FIG. 5 shows a cross-section of the Connector of FIG. 4 taken along the line 5-5;

FIG. 6 illustrates the attachment of circuit boards on adjacent faces of the block of FIG. 5;

FIG. 7 illustrates the assembly of a number of units as in FIG. 1 to form an assembly of circuit board interconnections for a composite circuit; and

FIG. 8 is a cross-section of a device as in FIG. 7, taken along the line 3-8.

As illustrated, the Connector of this invention may comprise a series of spring Contacts within an insulating body or block liti which is molded or otherwise formed of a plastic material, for example, diallyl phthalate preferably including reinforcing fibers.

The plastic material selected is of good insulation quality and of low moisture absorption, as well as of good surface characteristics such that moisture has little or no eifect upon the insulation value of the plastic block. The insulating block lil may be of any convenient length to accommodate a number of Contacting spring elements 11, each formed generally in U-shape with inwardly turned ends 13, to substantially encircle the block 10. Alternatively, the spring element may be of the form shown at 12, also of U-shape with inwardly turned ends 14 enclosing substantially three-quarters of the block 10.

In order to provide a universal insulating block for many purposes, a substantially square cross-section is illustrated in FIGS. 2, 3, 5 and 6, adapted to receive either contact springs Eli or 12. The form of block may be square or rectangular, the latter form being illustrated at 15 in FIGS. 7 and 8, in which one dimension has been reduced in order to provide for closer spacing of the terminal boards to be interconnected thereby.

The insulating block is provided with cut or formed Channels extending substantially therearound, each of sutticient depth to receive a spring element 11 or 12, and to permit its flexure therein without extending beyond the surface 16, 17, 18 or 19 thereof. Such grooves or Channels are illustrated at 21 in FIGS. 1 and 4, and are separated by lands 22 forming continuations of the surfaces 16, 17, ra and 19 of the block lil. To provide for the assembling of terminal boards upon the faces of the block, screw holes such as 23, preferably threaded, are formed at the ends or at suitable intervals along the length of the block to permit clamping of terminal boards A second threaded hole 24 is illustrated in the figures for the attachment of a terminal board at right angles to that Secured at bores 23. Ether the bores 23 or 24 may aiternatively be employed for securing the terminal block or connecter to a suitable mounting, whereby the terminal board itself may be supported.

in FIG. 3, there is illustrated a circuit board 25 having connecting elements 25 on one side thereof, two such boards being attached to the block 1 by means of screws 27 and 27 engaging bore 23. As shown in FIG. 6, one board 25 is Secured to the block by means of a screw 23 engaging bore 24, while one or two others are at right angles thereto Secured by screws as at 27. As shown in FIG. 7, the block 15 has similar bores receiving through bolts 29 for clamping together a number of blocks 15 between which may be inserted terminal boards. This Construction also admits of employnent of a terminal board such as 31 having contact strips 26 on one side and additional Contacts 32 on the other side thereof.

U It likewise permits the use in the same slot of a pair of thinner circuit boards such as 33 and 34 each with a set of Contacts on one surface thereof as at 35 and 56. The circuit boards 33 and 34 might, for example, be representative of a pair of plastic cables each having a plurality of conductors along one side thereof, the two plastic cables being inserted back-to-back in the same slot ,Where it might be desired to connect a terminal board such as 31 to a sheet cable such as 33.

As shown in FIGS. 7 and 8 a group of connectors may be assembled together on a common base 37 having end plates 38 perpendicular thereto and suitably spaced apart to permit the assembly therebetween of a group of blocks lil or blocks of the thinner form 35', each separated by spacers 39 and held together by through bolts 29. In an assembly such as in FIG. 7 it is convenient to employ the thinner form of insulator block 15 rather than the square form lt) illustrated in FIG. t since the necessity to conserve space may outweigh the desirability for the universal form of block.

The Contacting element of the connecter of this invention resides in a spring of form ti or llZ, or some variation thereof, one spring contact element being inserted in each channel 21. Channels 21 are preferably of square ection to receive springs lil or 12 formed of spring contact material generally of rectangular cross section. The spring elements may be of Phosphor bronze or other suitable non-corroding material and are preferably gold-plated to provide certainty of contact with conductors 26 on the printed circuit boards adapted to be interconnected thereto. Spring elements 11 and 12 are preferably of a width slightly less than the width of channels 21, providing only sulicient clearance between the spring elements and the channel walls to allow free movement of the spring elements.

A spring ii' of the form shown in FIG. 2, while generally of U-shape, extends to nearly a position from which the ends thereof may join, except that these ends are inwardly turned to form hook elements as at 3 to engage recess 41 formed in one side of the block lil. While various forms of spring element may be employed in the channels 21, a simple and convenient form is made of fiat wire bent slightly at the center as at 42 and further bent at 42' to form divergent lateral walls of a U-spring, biased to provide contact portions 43 and 44 which extend exteriorly of the channel 21, at the lateral faces when the portion 42 is within the channel on the face opposite to recess 4-1. Contact portions 43 and 44 are formed by providing additional slight bends in the spring elements thereat preferably cioser to the surface of the block 10 adjacent to the recess 41 to provide a longer spring action between the contact portions 43 and 44: and the base of the U at 42. Spring lll has additonal bends providing a pair of parallel portions 45 at either end thereof, the extreme end portions being bent essentially at right angles thereto as shown at 13 to provide hook elements for engaging the walls of the recess 41. A spring 11 so constructed is biased outwardly holding contact portions 43 and 44- exteriorly of the channels, the hook portions 13 serving to retain the spring within the channel except at contact points 43 and 44.

The base of channel 21 is provided With recess or well 41 in one face thereof opposite the bend 42 to receive the turned-in ends 13 of spring 11. Although the well 41 is shown as a single well it might be two separate recesses of the form shown at 47, each to receive one end 13 of spring 11. The form of the recess 41 or 47 is not critical but should provide for the receipt and retentior of the spring end and permit hook portions 13 to be moved laterally therein as portions t and 44 are depressed into channels 21.

The channel base is preferably provided with a relieved portion at each corner thereof shown at 48 and 49 such as to receive a narrower based spring 11 between points 42', 42' thereof inasmuch as the upper and lower branches of spring ll are ared outwardly from the bends 42'. The relieved portions 49 provide for a reccption of inwardly fiared portions of the spring between parallel portions 45 and the contact protrusions 4-3 and 44, the relieved portions of the channel bottom at 49 being of sufiicient extent to perinit depressing contact portions 43 and E-t entirely within the channel as the spring is bent near the center thereof.

A spring of the form shown at 12 has a central bend at 531 forming the base of a generally V-shaped portion wh ch is further bent at 52 on either side to form parallel portions 53, completing a generally U-shaped structure. Beyond the parallei portions 53 the spring 13 is bent additionally to conform to the direction of the channel 21 in two adjacent faces 54 and 55 of the block to, said faces being opposite a base portion 51 of the spring 12. Spring portions 56 and 57 are generally parallel to faces 5 and 55 and serve partially to retain the spring &2 Within the channel 21. Turned-in portions 14 are provided to engage walls of the recesses and 4-7, respectively. By this means, spring !12 is retained within the channel and may be biased to provide protruding portions 52 on adjacent faces 58 and 59 of the block ili). When constructed in this fashion, the spring 12 is adapted to intercornect contact eiements 26 of two printed circuit boards attachcd to the base i@ by bolts 27 and 28.

As shown in PLS. 6, securing of the circuit boards 25 to faces 53 and 59 depresses spring 12 in identical fashion as the depression of spring ll illustrated by the securing of circuit boards 25 to the block lt) by the boits 27 and 27'. it is further noted that either of the relieved portions 48 in the base of the channel 21 can accommodate a portion 53 of spring 12 in generally the same manner as the relieved portion 49 receives the inwardly turned portions of spring 11 beyond contact portions 4-3 and 44 of FG. 3. Thus, the relieved portion at the base of the channel serves different purposes, depending upon the spring employed. For this reason, the cross sectional form of block 1@ shown at the base of the channel has a generally octagonal form into three adjacent faces of which there are formed recessed or well portions 4-1 and 47.

in order that each block may be completely universal for each form of Connector, it is made symmetrical having a recess or well 47 on each face adjacent to face 55. Thus a spring of the form 12 may be inserted as shown in FIG. 5 having portion 57 at face 55 adjacent well 41 and portion 56 at face 54 adjacent well 47, or the portion 57 may be placed at face 59 of the block and the portion 55 at face 55 in the same manner as portion 57 as shown in FG. 5. Thus, one spring 12 may adapt one portion of block i@ to receive a panel 25 at the lower side of block lt, and another at the right side as shown in FIG. 6 for interconnecting portions thereof. Another spring 12 may be inserted in the channel 21 to interconnect a circuit board on the upper face 54 with one on the face 58 so that the same block ti) may be employed to interconnect two paraliel panels for some contact positions thereof and either of these panels with a thirri panel in other contact positions thereof. Likewise, the spring of the form 11 may be employed interchangeably With a spring of the form 12 and two panels may thus be arranged in parallel rclation for certain contact positions therebetween, while either such panel may be connected in other contact positions thereon to a third panel at right angles thereto.

in a device according to FIG. 7 or FIG. 8, a number of blocks 15 may be placed in position to receive parallel circuit boards, displaced by very narrow separation from each other, yet providing firm holding means for the circuit boards. A device manufactured as here disclose may consist of an insulating block lt) or 15 of any desired length, but is Conveniently manufactured in size very much smaller than illustrated. For example, the block 15 may have cross sectional dimensions of %i and inch, respectively, while the cross sectional dimension illustrated in FIG. 2 might be %s inch. When so constructed, it will be appreciated that circuit boards which are to be interconnected by means of the connector of this invention may be very closely spaced between the tcrminals on any such strip or board. It is thus readily possible to provide thirty double connections per square inch of surface occupied by the assembly of FIG. 7. In the event dual surfaces are exposed in each slot as when employing printed circuits such as 31 or 33 and 34, the number of connections is of course doubled. It will be appreciated that this is too close a spacing to permit soldered connections, there being insufficient room to permit assembly or disassernbly of the boards under ordinary circumstances.

The assembly as in FG. 7 permits inserting circuit boards in the several slots and thereafter securng them together by tightening bolts 29 when a rigid assembly is required. For this purpose, spacers 39 may be of slightly smaller thickness than the thickness of the circuit boards and one end 38 of the assembly may be detachable from the base 37 in order to provide for adjustable take up to firmly clamp the boards in position between the faces of the block 15.

It will be appreciated by those familiar with printed circuit connector boards that an etficent and compact connector is achieved by the Construction herein described and that use of spring elements 11 and 12, interchangeably on a symmetrical block 10, provides a universal base structure for making connections of many kinds and for assernbling circuit boards in various configurations mutually parallel or perpendicular to each other. Any desired degree of pressure between circuit boards and blocks may be assured. At the same time, a structure is provided in which the Channels protectively receive therein spring members 11 and 12, extending slightly beyond the lateral faces where contact is desired With the terminal board. Upon assembly of the terminal boards against such faces, the springs are depressed within the channel so as to accornmodate lost motion of the hooked ends thereof within the recesses or wells 41 or 47 in a manner to prevent any overstressing of the spring as it is depressed. It will be seen that circuit boards may be reassembled in this way any number of times, employing the same connectors, without in any manner causing deterioration of the spring members themselves. Such a Construction makes it impossible to damage the spring contact elements by overpressure, and an improved reliability is obtained.

While the invention has been described with respect to particular embodiments it is obvious that many modifications and variations are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A connecter for a plurality of printed circuit strips arranged in linear array comprising an clongated block of insulation material of generally square cross section,

plural transverse Channels each formed within the faces of said block and extending therearound between lands thereof, and

contact spring retaining means including at least a pair of recessed wells formed in the bottom of each said channel,

each said well extending toward the center of the block, each said Well being constructed to receive a contact spring turned thereinto after passing around more than three sides of the block in said channel, said wells being of sufficient Width to permit lost motion of a spring as it is depressed into said channel at an adjacent side of the block, one said well of at least one said channel being constructed to permit said motion for terminations at both ends of a said contact spring extending substantially around said block.

2. A printed circuit connector comprising an elongated body of insulating material of rectangular section having plural contact faces,

said body having peripherai Channels extending transversely therearound between lands of said faces, including one said channel for each circuit connecter position,

a recess within the bottom of each channel in each of two adjacent said faces, said recesses having lateral wall portions one of which is spaced a predetermined distance from an adjacent contact face,

a contact spring extending around substantially three sides of said body within each said channel and forrned with inwardly turned ends each loosely fitting within one said recess to retain said spring in the channel, each contact spring being forned to include sprin contact portions which extend exteriorly of said channel at said contact faces,

a circuit board for each of two said contact faces, said circuit boards including surface contact elements, one fer each connection to be made, means for attaching said circuit boards to said contact faces to cause said springs to be depressed below said lands and within said channels, respectively, to maintain contact pressure on said elements.

3. A printed circuit board Connector comprising an elongated insulating body of rectangular cross section having a plurality of circuit board contact faces,

a circuit board secure-d to each of two said faces, each said board having surface conductor elements spaced along an edge thereof adjacent one said face,

a plurality of channels peripherally about said body within said faces including at least one recess at the bottom thereof to loosely receive contact spring terminations, said channels being arranged along said body adjacent said conductor elements,

a contact spring in each of a plurality of said Channels having a protruding contact portion for each of said two faces, each spring having a pair of hooked ends each inwardly turned to engage one said recess peripherally beyond said two faces,

each said recess extending inwardly to receive said end and laterally to permit lateral motion thereof, as a said board is Secured to a corresponding said face,

and said contact springs being formed to be thereby depressed at said contact portions, each to interconnect a pair of corresponding said portions of said circuit boards.

4. A circuit board Connector comprising an elongated insulator block of substantially square section,

a plurality of rectangular channels each extending continuously around at least three sides of said block,

a plurality of recesses in the inner surface of each said channel at adjacet lateral sides thereof,

a spring' contact element in each said channel having inwardly turned ends,

said elements extending in said channets around substantialiy three sides of said block,

said inwardly turned ends loosely engaging recesses to retain said springs therein,

said springs having plural contact portions extending exteriorly of said Channels on two sides of said block,

and said recesses being of sufficient lateral extent to allow depression of said contact portions entirely within said Channels.

5. The Connector of claim 4- wherein said Channels eX- tend around substantiaily four sides of said block.

6. The Connector of claim 4 wherein said recesses are in three adjacent sides of said block, and said spring elements engage recesses selectively within any two said adjacent sides.

&173332 7. A circuit board connecter comprising an elongated insulator block of rectangular section,

a plurality of Channels extending substantially around said block,

a spring contact element in each said channel having inwardly turned ends, said spring elements extending around at least parts of three sides of said block,

recess means within each said channel loosely engaging said ends to prevent dislodgment of said spring therefrom,

said spring elements each having :two outwardly biased contact portions extending, when not in contact with a said circuit board, exteriorly of said Channels,

and said recess means being constructed to permit depressing 'said contact portiors within said channel upon contact with a said board.

8. The Connector of claim 7 having at least one said spring element extending around three sides of said block with said recess means in a fourth side thereof.

9. The Connector of claim 7 having at least one said spring element extending around two -sides of said block with said recess means in said third and fourth sides thereof.

10. The connecter of claim 9 having at least one said spring element extending around three sides of said block With said recess means in a fourth side thereof, others thereof being arranged to contact circuit boards disposed at right angles, at least one said spring element being arranged to contact parallel spaced circuit boards.

11. A plurality of connectors according to claim 7 arranged in juxtaposition,

having adjacent sides thereo equipped with said contact portions, wlereby a circuit board inserted therebetween is contacted by said por tions of a pair of said connectors.

12. A pair of connectors according to claim 7 adjacently arranged for mutual connection to a said circuit board, and clamping means securing at least one said circuit board between said connectors.

13. In a circuit board interconnector having lateral surfaces for Contacting a plurality of circuit boards, an insulating body of substantially square transverse section, a plurality of transverse channels extending substantially around said body, separated by lands extending to form said section, said channels having roughly square cross sections parallel to said transverse section between said lands, recess means in two adjacent bottom portions of each said channel to receive and retain inwardly turned spring ends therein, spring contact means in each said channel extending around at least three-quarters of the length of each said channel, each contact means having an inwardly turned end loosely within a said recess means, and a contact portion extending normally eXteriorly of said channel on two faces of said body, said portion being proportioned for inward movement within the channel as a surface is pressed against said lands.

References Cited in the file of this patent UNITED STATES PATENTS 2,699,534 Klosterrnann Jan. 11, 1955 2,832,942 French Apr. 29, 1958 2,870,424 Franz Jan. 20, 1959 2,942,229 Berger June 21, 1960 2,944,121 Wasylenko July 5, 1960 

3. A PRINTED CIRCUIT BOARD CONNECTOR COMPRISING AN ELONGATED INSULATING BODY OF RECTANGULAR CROSS SECTION HAVING A PLURALITY OF CIRCUIT BOARD CONTACT FACES, A CIRCUIT BOARD SECURED TO EACH OF TWO SAID FACES, EACH SAID BOARD HAVING SURFACE CONDUCTOR ELEMENTS SPACED ALONG AN EDGE THEREOF ADJACENT ONE SAID FACE, A PLURALITY OF CHANNELS PERIPHERALLY ABOUT SAID BODY WITHIN SAID FACES INCLUDING AT LEAST ONE RECESS AT THE BOTTOM THEREOF TO LOOSELY RECEIVE CONTACT SPRING TERMINATIONS, SAID CHANNELS BEING ARRANGED ALONG SAID BODY ADJACENT SAID CONDUCTOR ELEMENTS, A CONTACT SPRING IN EACH OF A PLURALITY OF SAID CHANNELS HAVING A PROTRUDING CONTACT PORTION FOR EACH OF SAID TWO FACES, EACH SPRING HAVING A PAIR OF HOOKED ENDS EACH INWARDLY TURNED TO ENGAGE ONE SAID RECESS PERIPHERALLY BEYOND SAID TWO FACES, EACH SAID RECESS EXTENDING INWARDLY TO RECEIVE SAID END AND LATERALLY TO PERMIT LATERAL MOTION THEREOF, AS A SAID BOARD IS SECURED TO A CORRESPONDING SAID FACE, AND SAID CONTACT SPRINGS BEING FORMED TO BE THEREBY DEPRESSED AT SAID CONTACT PORTIONS, EACH TO INTERCONNECT A PAIR OF CORRESPONDING SAID PORTIONS OF SAID CIRCUIT BOARDS. 